Clamping means for retaining electric plug and socket connectors



March 4, 1969 A, s. KLINGENBERG- CLAMPING MEANS FOR RETAINING ELECTRIC PLUG AND SOCKET CONNECTORS Sheet Filed 060. 23, 1966 m/vs/vrolv A. S. KL/NGENBERG March 1969 A. s. KLINGENBERG 3,431,537

CLAMPING MEANS FOR RETAINING ELECTRIC PLUG AND SOCKET CONNECTORS Filed Dec. 23, 1966 Sheet 2 01'2 r J ll/Ii 3 Claims ABSTRACT OF THE DTSCLOSURE A clamping device for firmly holding a pair of plugs mounted in receptacles on a panel. The device comprises a rod having a pin at its lower end adapted to be received and held within a socket located between the receptacles on the panel. The rod carries a coiled spring which has its upper end held by an enlargement on the rod while its lower end is adapted to be pressed against a bracket which is slidably mounted on the rod. The upper portion of the bracket is formed with two cross-portions extending outwardly from its center and provided with flanges having downwardly extending locking portions. The in sertion of the rod into its socket compresses the spring thereby forcing the crosspieces and their flanges firmly against the tops of each of the plugs. The two locking portions of the flanges engage side portions of the plugs so as to prevent the bracket from tilting and slipping off the tops of the plugs.

This invention relates to an improved clamping device for releasably holding a pair of electric plugs firmly in electric receptacles and, more particularly, for releasably holding coaxial plugs securely in inserted positions which are relatively inaccessible.

Heretofore, clamping devices have been provided for holding ordinary household electric plugs in conventional wall outlet sockets. The purpose of these clamping devices is to prevent the plugs from falling out of the sockets as well as to prevent them from being accidentally hit and knocked out of the sockets. All that is required of these prior art clamping devices is that they press or hold the plugs sufliciently far into the sockets for electric connection to be maintained therebetween. This objective can be accomplished without pressing the plugs fully into the sockets because electric connection can be established even if the plugs are not inserted all the way into their sockets.

A different situation exists in the case of coaxial plugs because these plugs must be fully inserted and held all the way into their sockets. The reason for this is that, if a coaxial plug is not fully inserted into its socket, the electrical length of the associated coaxial cable becomes increased by the amount of the plug that is not inserted, no matter how small this may be. As is well known in the art, any change in the electrical length of a coaxial cable produces a change in the phase of the electric wave conveyed by the cable. Such phase changes are objectionable because they impair the operation of precisely designed electric circuits. Furthermore, partly open coaxial connections create impedance mismatches which produce undesirable standing waves.

Accordingly, it is an object of this invention to provide improved clamping means for releasably holding 3,431,537 Patented Mar. 4, 1969 electric plugs, particularly coaxial plugs, firmly in inserted positions in electric receptacles.

An additional object of the invention is to provide improved clamping means for releasably holding electric plugs securely mounted in electric receptacles which are relatively inaccessible.

These and other objects of the invention are attained by providing a clamping device which comprises a rod having a pin at its lower end which is adapted to be received and held within a socket that is located between a pair of electric receptacles mounted on a panel. The rod carries a coiled spring which has its upper end held by an enlargement on the rod while its lower end is adapted to be pressed against a bracket which is slidably mounted on the rod. The upper portion of the bracket is formed with two cross-portions extending outwardly from its center and provided with flanges having downwardly extending ears or locking portions.

The insertion of the rod into its socket serves to compress the spring thereby applying a predetermined fixed force to the center of the bracket. This force is equally distributed to each side of the bracket and causes the cross-portions and their flanges to be pressed firmly against the tops of each of the cylindrical plugs. The two ears or locking portions of the flanges engage side portions of the plugs so as to prevent the bracket from tilting and slipping off the tops of the plugs.

These and other features of the invention are more fully discussed in connection with the following detailed description of the drawing in which:

FIG. 1 is a front elevational view of a clamping device in accordance with this invention;

FIG. 2 is a front elevational view of a modified embodiment of the clamping device mounted on two coaxial electric plugs for holding them in inserted positions in a pair of coaxial electric receptacles;

FIG. 3 is a front elevational view of a slightly diflerent modified embodiment of the clam-ping device mounted on both a supporting bracket and a single coaxial electric plug for holding the plug securely in a coaxial receptacle mounted on a panel; and

FIG. 4 is a perspective view of a plurality of coaxial electric plugs inserted in coaxial electric receptacles and held firmly therein by the clamping means of this invention.

In the exemplary embodiment of the invention that is shown in FIG. 1, the clamping device is represented as comprising a reach-rod 1 having a knurled knob, or handle, 2 at its upper end and a transverse pin 3 near its lower end. A bracket 4 is slidably mounted on the lower portion of the rod 1. A convenient method of mounting the bracket 4 is to bend its top and bottom central portions into flanges 5 and 6, as is best seen in FIG. 4, and then drill holes in them of sufiicient size for easily admitting the rod 1 therein.

The upper portion of the bracket 4 is formed with two cross-portions 7 and 8 which extend outwardly from the central part of the bracket 4. The end of each of these cross-portions 7 and 8 is curved and bent to form side flanges 9 and 10, respectively. The flanges 9 and 10 are each provided with ears 11 and 12, respectively, which are constituted by downwardly extending portions which function as locking members. These flanges 9 and 10 and their ears 11 and 12 are best seen in FIG. 4.

A coiled spring 13 is slidably mounted upon the rod 1 by passing the rod 1 through the center of the spring 13. The upper end of the spring 13 is adapted to abut against an enlargement on the rod 1. This enlargement is conveniently constituted by a collar 14 mounted on the rod 1 and held securely in position by a set screw 15. The lower end of the spring 1-3 is adapted to be pressed against the top flange of the bracket 4.

A modified embodiment of the invention is represented in FIG. 2 as having a somewhat similar coiled spring 16 which is slidably mounted on the lower portion of the rod 1 within the space covered by the bracket 4. The top of this spring abuts against a collar 17 which is securely attached to the rod 1 by a set screw 18. The lower end of this spring 16 is adapted to be pressed against the lower flange 6 of the bracket 4. If desired, a washer 19 can be interposed between the end of the spring 16 and the top surface of the flange 6. Since the clamping device is illustrated in FIG. 2 as being in an operated condition, the coils of the spring 16 are compressed. Normally, the spring 16 is not so compressed and it pushes the rod 1 upward so that the collar 17 carried thereon is closer to the upper flange 5 of the bracket 4.

Another modified embodiment of the clamping device is illustrated in FIG. 3. This form of the invention is similar to the embodiment shown in FIG. 2 but is provided with an additional flange 29. The flange 2'8 is formed by partly cutting out a portion of the bracket 4 and then bending this portion upward. A hole is drilled through the flange for admitting the rod 1. This additional flange 20 functions to provide better support for the rod 1 so that it will be less liable to become bent.

The clamping device of this invention can be used for holding various types of plugs. However, as was stated above, it is particularly useful for holding coaxial plugs that are mounted in coaxial receptacles which are relatively inaccessible. An example of this last-mentioned type of use is illustrated in FIG. 4 which shows a number of cylindrical coaxial plugs 21, each having a flat edge 35 around its top, inserted in coaxial receptacles 22 that are closely spaced together on a panel 23. In this particular example, the plugs 21 are located at the ends of a number of coaxial jumper cables 24. Each of these cables has its end portions enclosed within a protective coiled spring 25 and has its intermediate portion enclosed within a protective metallic tube 26.

Although only a few of the cables 24 are shown in FIG. 4, the actual project requires several thousands of them. Due to the large number of closely located associated receptacles 22, many of them are relatively inaccessible. It is for this reason that the reach-rod 1 is provide with a long handle portion so that the pin 3 and the bracket 4 can be inserted between the closely spaced cables 24. Furthermore, the panel 23, which is shown in a horizontal position for the purpose of simplicity, is actually mounted in an inverted slanting position thereby subjecting the cables 24 to the hazard of falling out of the receptacles 22. This is another reason why the plugs 21 should be securely clamped in their receptacles 22.

The panel 23 is equipped with a number of sockets 27 which are located between the receptacles 22 in the manner shown in FIG. 4. These sockets 27 are designed to receive and hold the transverse pins 3 at the bottom portions of the reach-rods 1. The sockets 27 may be of any suitable construction known to those skilled in the art. One appropriate construction is that disclosed in Patent 3,152,822 issued Oct. 13, 1964 to E. G. Griffiths which includes a locking mechanism that is adapted to grip the pin 3 securely when the reach-rod 1 is pushed into the socket. This locking mechanism is designed to release the pin 3 in response to a second push upon the reach-rod 1. Thus, this type of socket furnishes a convenient means for holding and subsequently releasing the reach-rods 1 because it locks a reach-rod 1 in response to the first push thereon and then releases it in response to a second push.

Accordingly, when any one of the illustrated three forms of the clamping device is to be used, it is grasped by its handle or knob 2 and the lower end of its reachrod 1 is then inserted in the desired socket 27. In so doing, the bracket 4 is passed laterally between two cables 24 that have their plugs 21 inserted in those receptacles 22 that are located on each side of this particular socket 27. The knob 2 is then turned for rotating the bracket 4 so that its cross-portions 7 and 8 can be brought to bear against the coiled springs 25 on these cables 24. In other words, this part of the bracket 4 is so placed as to straddle the tops of the plugs 21 at the ends of the cables 24.

In thus positioning the bracket 4, its side flanges 9 and 19 become partly wrapped around the coiled springs 25 and its downwardly extending ear portions 11 and 12 are fitted over the tops of the plugs 21 so as to bear against the front vertical cylindrical portions thereof. The knob 2 is then pushed down thereby causing the abovementioned locking mechanism in the socket 27 to grip and hold the transverse pin 3 at the end of the reachrod 1. This serves to lock the clamping device in the position shown in FIGS. 2 and 4.

It is to be noted that, when the knob 2 is pushed down, the distance between the collar 14 and the flange 5 in FIG. 1 will be reduced. Similarly, in the forms of the invention shown in FIGS. 2 and 3, the distance between the collar 17 and the flange 6 will be shortened. These actions cause the springs 13 and 16 to be subjected to a predetermined fixed amount of compression due to several factors. One of these is that the locking mechanism in the sockets 27 limits the extent of the downward movement of the pins 3 therein. Another is that the position of the collar 14 or 17 fixes a limit for the upper end of the spring 13 or 16. A third factor is that the location of the flange 5 or 6 determines the limit for the lower end of the spring 13 or 16. All of these factors, as well as the characteristics of the spring 13 or 16, are adjusted in advance so as to produce the desired degree of compression.

Thus, the fixed compression of the spring 13 or 16 produces a predetermined fixed amount of compressional force which tends to drive the bracket 4 downward. The cross-portions 7 and 8 together with their flanges 9 and 10 function as load-distributing means for distributing this compressional force. Since the cross-portions 7 and 8 and the flanges 9 and 10 are symmetrical about the center of the bracket 4, they will distribute the applied compressional force equally to the flat top surfaces 35 of the plugs 21 in each pair. This serves to hold the plugs 21 securely in their inserted positions in the receptacles 22.

If the clamping device should be accidentaly struck or pushed, it will not become disengaged from the plugs 21 due to several factors. The first is that the ears 11 and 12 are fitted against the front surfaces of the plugs 21 so as to prevent the clamping device from tilting backward. Another factor is that the cross-portions 7 and 8 abut against the backs of the protective springs 25 and prevent the clamping device from tilting forward. Sideward movement of the clamping device is prevented by the engagement of the flanges 9 and 10 with the sides of the protective cable springs 25. Thus, the clamping device will remain securely in its desired position.

When it is desired to remove any of the plugs 21 from their receptacles 22, this can readily be accomplished by pushing the knob 2 downward thereby causing the locking mechanism in the socket 27 to disengage the transverse pin 3. This, in turn, releases the compressional force on the spring 13 or 16 thereby removing the pressure previously exerted upon the bracket 4. The bracket 4 can now be completely removed by lifting up the knob 2, and the plugs 21 can then be taken out of their receptacles 22 by pulling upward on the metallic tube 26.

Although the clamping device of this invention has thus far been described as being employed for holding a pair of plugs 21, it can also be used for retaining only one plug 21 in its receptacle 22. This can be accomplished by utilizing a bracket 28 for supporting one end of the bracket 4 in the manner illustrated in FIGS. 3 and 4. The sides of the bracket 28 are bent for forming two flanges 29 having their lower portions so fashioned as to form two spring fingers 30 and 31 which are adapted to engage two screws 32 that are mounted on the panel 23 at 0pposite sides of any of the sockets 27. If desired, the screws 32 may be driven all the way into the panel 23, as is shown in FIG. 4, when no bracket 28 is attached to them. The upper portion of the bracket 28 is bent for forming a flange 33 which is so constructed that, when the bracket 28 is mounted on the panel 23, the top of the flange 33 is on the same horizontal level as the top of the plug 21 that has been inserted in a receptacle 22.

The bracket 28 functions to support and hold the flange 9 of a bracket 4 during the time that the associated flange 10 is clamping a single one of the plugs 21. If desired, the top edge of the flange 33 and the bottom edge of the flange 9 on the bracket 4 may both be notched as is indicated by the reference numeral 34 in both FIGS. 3 and 4. The mutual engagement of these notches 34 serves to hold or lock the flange 9 securely in its proper position upon the top edge of the flange 33 and prevents it from slipping or being accidentally struck and knocked out of place.

What is claimed is: 1. Improved clamping means for firmly holding a pair of plugs detachably inserted in a pair of receptacles,

each of said plugs having a cylindrical body with a flat top having a cylindrical cable extending therefrom, each of said tops having a flat annular surface surrounding said cable, said clamping device comprising a bracket having a central portion with a cross-portion formed on each side thereof for engaging said flat annular top surface of each of said plugs, spring means for pressing said cross-portions against said flat top surfaces of said plugs for firmly holding them, and each of said cross-portions having its end curved and bent into a flange for engaging a respectively different one of said cables. 2. Improved clamping means in accordance with claim 1,

and further including means for holding said cross-portions from tilting and falling off said flat top surfaces of said plugs,

said last-mentioned means comprising downwardly extending ear portions formed at the end of each of said curved flanges for engaging the cylindrical bodies of said plugs.

3. Improved clamping means comprising a reach-rod having a handle at one end and a transverse pin at the other end,

said pin being adapted to be inserted and releasably held in a locking mechanism,

a bracket having a central portion with two flanges formed thereon,

means defining a hole in each of Said flanges for slidably receiving therein said rod,

said bracket having two cross-portions extending outwardly from opposite sides of said central portion, each of said cross-portions having its end curved and best for forming a side flange,

the bottom edges of said cross-portions and said side flanges being adapted to engage the tops of objects that are to be clamped,

said side flanges having downwardly extending portions forming ears adapted to engage the sides of said objects, and

a coiled spring slidably mounted on said rod and adapted for pressing said bracket in response to the insertion of said pin in said locking device whereby said cross-portions together with their side flanges and ears are pressed against said objects.

References Cited UNITED STATES PATENTS 452,527 5/ 1891 McElroy 248-361 1,011,594 12/1911 Dunham. 1,427,347 8/ 1922 Bauder. 3,005,176 10/1961 Berg.

FOREIGN PATENTS 715,611 1/1942 Germany.

MARVIN A. CHAMPION, Primary Examiner;

JOSEPH H. MCGLYNN, Assistant Examiner.

US. Cl. X.R. 

